Llanedeyrn (Welsh: Llanedern) is a district and community in the east of the city of Cardiff, Wales, located around 3.5 miles from the city centre. The parish of Llanedeyrn rests on the banks of the river Rhymney and is visible nesting on a hill side above the A48(M), westbound on the approach into cardiff.
The name "Llanedeyrn" is believed to be derived from a sixth-century prince and a Celtic saint named St. Edeyrn or Edern. During the sixth century, St. Edeyrn and a fellow monk, St. Isan, were given the task of spreading the faith and establishing places of worship. The first location chosen by the two monks was Llanishen. This area commemorates the first of the two monks St. Isan (Llan + Isan) and the other St. Edeyrn (the word "Llan" means settlement or place of worship in the Welsh language). St. Edeyrn was reputed to have travelled widely and as a result there are churches in North and South Wales dedicated to his memory. St. Edeyrn gathered together a community of about 300 that lived and worshipped in the Llanederyn area.
The original Norman style church dating back to 1123 exists only as stonework remnants beneath restoration work completed in 1888, the church today is a simple structure featuring a tower and five bells. Adjacent to this church is a public house called the Unicorn. The building dates to the 14th-century and was converted in the late 18th-century. 
Nearby in Pen-y-Groes a Calvinistic Methodist school room and chapel was erected in 1840.
Comprising only a tiny number of buildings, Llanedeyrn became part of Cardiff in 1889. 
In the late 1960s, Cardiff Council decided to create low cost social housing in Llanederyn, with an estimated 3,500 homes to be erected for 12,000 less well off people (2,000 homes owned by the city council and 1,500 private homes). The first of the estates within the area was opened in 1968. The council provided a selection of prefabricated and terraced houses and numerous 2, 3 and multi-storied flats were constructed.
In 1974 the Maelfa shopping centre was built and a part-time police station was set up, followed shortly in 1975 by the Retreat public house adjacent to it. The public house The Pennsylvania, dating from 1972, closed down and reopened in 2004 as the New Penn.
The housing estates contained within the area of Llanedeyrn are:
In 2016 Llanedeyrn became one of four new communities in Cardiff, having previously been part of the Pentwyn community. However, like many communities in Cardiff, it does not have a community council.
- "The History Of Cardiff's Suburbs - Llanedeyrn and Pentwyn". Cardiffians.co.uk. Retrieved 9 April 2017.
- "The New Penn". Cardiffpubs.co.uk. Retrieved 9 April 2017.
- Ruth Mosalski (23 March 2015) "No longer will housebuyers be able to mock estate agents... Pontcanna is set to be one of four city 'areas' given official status", Wales Online. Retrieved 9 April 2017.
- The City and County of Cardiff (Communities) Order – 2016 No. 1155 (W. 277) (PDF). Welsh Statutory Instruments. 2016. Retrieved 9 April 2017.
- Population Statistics (1841 - 1891)
- St. Ederyn's church, monumental inscriptions
- http://www.walesdirectory.co.uk/Towns/Llanedeyrn.htm - The unicorn pub